we need to protect their environment. we have a strict quarantine system to protect the integrity of the environment. forty years on, it's still a class-a nature reserve. it's our job to look after them. ...it's my job to look after it. ♪ >> people typically don't admit sexual assaults and murders to police officers unless, many of the, they probably have done it. so it was clear, we felt, he was responsible for the tricia reitler disappearance. >> she had such a zest for life. and she would walk in the room and everybody knew she was there. >> tricia reitler, a 19-year-old psych major at indiana wesleyan university was on her way to becoming a family counselor. >> her goal was to be able to put families back together again. >> then, in march 1993, donna and gary reitler received that late-night phone call every rent dreads, a cop from marion, indiana, was on the line. >> he said, do you know where tricia is? in my heart, i knew that something was drastically wrong. >> tricia had walked to an off-campus supermarket, and